Internal grinding machine



Feb. 25, 1958 .J. w. PARKER 2,824,412

INTERNAL GRINDING MACHINE Filed July 7, I955 Y s Sheets-sheaf, 1

. INVENTOR. @1 71 V/ frZer Feb. 25, 1958 J..W. PARKER INTERNAL GRINDINGMACHINE Filed July 7, 1955 s Sheets-Sheet 2 7 mmvrox .7227! M FarXe 7' IFeb. 25, 1958 J. w. PARKER 2,824,412

' INTERNAL GRINDING MACHINE Filed July 7-, 1955 6 Sheets-Sheet 3 w 721/:M1- I INVENTOR. J23? 14 ;%zr%e7' Tax/vrK st J. W. PAR KER INTERNALGRINDING MACHINE" Feb. 25, 1958 v .6 Sheets-Sheet 4 Filed July '7, 1955INVENTOR. V/ 247%.? 7

LYZZW 1958 J. w. PARKER INTERNAL GRINDING MACHINE s Sheets-Sheo 5 FiledJuly 7, 1955 Feb. 25, 1958 v J. w. PARKER IfiTERNAL GRINDI NG MACHINE 6Sheets-Sheet 6 Filed July 7, 1955-- INVENTOR.

BY v \2 N $7202? 49%. IVE/Sf United States Patent P INTERNAL GRINDINGMACHINE John William Parker, Grosse Pointe, Mich.

Application July 7, 1955, Serial No. 520,420

14 Claims. (Cl. 51-95) This invention relates to machines and moreparticularly to grinding machines or the like.

While the principles of the invention are applicable to diverse types ofpower machinery, they are exemplarily embodied in an internal grinderprimarily employed to grind an aperture or socket in a workpiece to aprecise diameter or taper.

The features herein described and claimed evolved from an efiort toprovide the industry with a compact, relatively low cost grindersuitable for single-piece manually controlled grinding operations, whileat the same time adapting the grinder to semiautomatic operation so thatthe smaller shop, with a reasonable investment, can produce quantitiesof identical parts on a competitive basis.

In general, in the disclosed embodiment of the invention, a workpiece isrotated about and reciprocated along the longitudinal axis of theaperture or socket which is to be ground, by means of a workhead mountedupon a reciprocating table. A grinding wheel is positioned to engagethat aperture or socket and is independently rotated about itslongitudinal axis. A cam-actuated sizing unit, driven by thereciprocating table, supports and incrementally feeds the grinding wheelinto the work, transversely of the line of table reciprocation, on acyclic basis. The point in the stroke of the table at which theincremental feed occurs, and the amplitude of the increment, may both beadjusted.

The sizing unit as a whole may also be moved transversely of the line oftable reciprocation for manually controlled grinding and for initialsetting preliminary to semiautomatic operation.

A Wheel dresser is employed not only to insure that the surface of thegrinding wheel is in proper condition, but also as a primary element ofthe sizing control in semiautomatic operation of the mechanism.

A feature of the invention is an improved automatic crossfeed mechanism.

Another feature of this invention is an improved means for actuating acrossfeed mechanism by the reciprocations of a longitudinal feed table.

Another feature of this invention is an improved mechanism for applyingbalanced forces to move a rotating spindle evenly, precisely and withoutbinding.

A further feature of this invention is a circuit arrangement forautomatically initiating and terminating the operation of driving motorsas a function of the cyclic operation of a crossfeed mechanism and as afunction of the position of a reciprocable table.

Another feature of this invention is an improved method ofsemiautomatically grinding a plurality of workpieces.

The detailed nature of the foregoing features, and other features of theinvention, will be perceived from the following detailed description ofan embodiment of the invention when read with reference to theaccompanying drawings in which:

Figure 1 is a perspective view of an internal grinding ,machineembodying the principles of the invention;

2,824,412 Patented Feb. 25, 1958 ice Fig. 2 is an enlarged, fragmentary,front elevational view of a portion of the mechanism represented in 1;Fig. 3 is a sectional view taken substantially along the line 3-3 ofFig. 1, showing the automatic sizing unit in side elevation and aportion of the mechanism for driving that unit;

Fig. 4 is an enlarged perspective view of the wheel dresser shown inFig. 1;

Fig. 5 is a sectional view taken substantially along line 5--5 of Fig.3;

Fig. 6 is an enlarged view of the actuating cam mechanism of theautomatic sizing unit;

Fig. 7 is a sectional view taken substantially along the line 7--7 ofFig. 3;

Fig. 8 is a fragmentary perspective view looking generally in thedirection of the arrow 8 in Fig. 1 of the drawings;

Fig. 9 is a sectional view taken substantially along the line 99 of Fig.3;

Fig. 10 is a sectional view taken substantially along the line 10-10 ofFig. 9; and

Fig. 11 is a representation of an electrical system for controlling themotors represented in Fig. 1.

While the machine shown in Fig. 1 of the drawings is adaptable to avariety of uses, and while the principles of the invention are even morebroadly applicable, it is assumed that an internal grinding operation isto be performed upon each of a plurality of workpieces. A workpiece isnormally mounted in a chuck 14 so that the aperture or socket thereinwhich is to be ground and the chuck have a common longitudinal axis.Chuck 14 is rotatively driven by a conventional workhead 16, including amotor 18.

The workhead 16 is rigidly mounted, through its base 20, to a table 22.Table 22 is supported upon slides 24 and 26 (Fig. 3) on a base 28 sothat the table 22, and hence the workhead 16, may be reciprocatedrelative to the base 28.

Reeiprocation of the table 22 relative to the base 28 may be performedmanually or automatically. Manual control of the movement of the table22 is exercised through a hand-feed wheel 30 which drives the tablethrough a conventional rack-and-pinion arrangement (not shown).Alternatively, the table 22 may be reciprocated relative to the base 28by means of a table drive motor 32 which is connected to drive, throughconventional the gearing not shown, a wheel 34. Wheel 34 is providedwith an eccentrically mounted pin 36 engaged by a link 38 which servesto oscillate a bellcrank 40 about a pivot pin 42. To transform theoscillatory motion of bellcrank 40 into translational motion of thetable 22, the upper end of bellcrank 40 is clasped between a stop 44 anda latch 46 (Fig. 2), both of which are secured to but adjustable alongthe length of the table 22. By shifting the positions of stop 44 andlatch 46, both the length of the stroke and the position of the strokemay be adjusted.

Latch 46 is mounted upon a bar 48 which is vertically slideable relativeto its support member 49. Latch 46 is biased downwardly, as shown, bygravity supplemented, if necessary, by a biasing spring (not shown). Thesupport member 49 is attached to the table 22 and may be adjustablypositioned along the length thereof.

The upper arm of bellcrank 40 may be momentarily disa pivotallyandpendently "supported on the bracket 47 by a pin 53. Lever 52 can freelymove through an arc in a counterclockwise direction, but clockwisemovement is prevented by a stop pin 55 mounted on bracket 47.

When table 22 is moved to the left, as 'noted above, trip lever 52strikes the actuating arm 51 of limit switch LS1. However, lever 52 doesnot actuate limit switch LS1 since in this direction lever 52 freelypivots, rides over arm 51, and drops back to its normal position (Fig.2) upon clearing and moving to the left of arm 51.

When table 22 is again moved to the right by 'hand wheel 30, trip lever52 again strikes actuating arm 51 and since stop 55 (Fig. 2)preventsclockwise rotation of lever 52, arm 51 is actuated to operatelimit switch LS1. In being so actuated,'arm"51 is pivoted in aclockwiscdirection (Fig. l) and is cammed out of thepath of lever 52 so that thetable 22 can continue to moveto theright. Thus, limit switch LS1 is notoperated as table "22 is moved to the left, but is'momenta'rily-operatedas table 22 is returned to the right.

As table 22 is moved further to the right, the cam surfaceon theloweflriighhhandface oflatch46 (Fig. '2) strikes the upper end ofbellcrank 40, driving latch 46 upwardly and over'the bellcrank end. Ator prior to the point at which the upper end 'of crank 40 strikes stop44, latch 46 will have cleared the bellcrank and will restore to theshown latching position.

If the length of the requisite stroke is longer than that provided bythe reciprocator mechanism including bellcrank '40, a powerfeedmechanism may be provided of any suitable type'known in the art. Thus,motor 32 may be of the reversible type, with its direction of rotationcontrolled by limit switches LSI'and LS3 which may be actuated in anyappropriateimanner at each end of a selected stroke.

It is customary to supply coolant to the work during machine grindingoperations andmeans including coolant pump and motor 54 may be providedto supply an appropriate coolant liquid either as a stream directed atthe grinding wheel and work exteriorly of theapparatus, or as a streamflowing through a central orifice (not shown) through the workhead 16andchuck 14 to flood the. inner surface of the workpiece.

The grinding wheel 58.(Figs. l and 8) is both rotated and crossfed bymeans including an automatic sizing unit 60. Unit 60 is supported uponways 61 (Fig. 8) along which it may slide 'in a direction perpendicularto the direction of motion of the table"22. Waysf61 are formed on theupper surface of a cross-feedbed'29, integral with base28. The unit'60is movedupon the ways 61 by means including a verniercross-feedmechanisrn 63 (Fig. I). This cross-feed mechanism, whichmay beof any conventional type well known in the art,may be employed duringmanually controlled grinding operations and is also employed toestablis'han initial'position of the automatic sizing unit 60preparatory to automatic operation of the machine.

The automatic sizing unit 60 comprises abodycasting 62 including a pairof forwardly extending,'parallel, annular support members 64, serving asa'bracket, as may best be seen in Figs. 8 and 9 of the drawings. Eachannular support member 64 carries a'bearing 66 afiixed within itscentral bore by means such as machine screws 68. The reduced endportions of a shaft 69 are rotatably seated in the 'two bearings 66. Thebearings 66 are preferably closed by means suchas plugs 70, one of whichmay be tapped to accept an oiler'72 arranged to flow oil through achannel 74in the shaft 69 and thence to the bearing surfaces.

Shaft 69 supports a rocker assembly including a rocker casting 76 theupper end of whicli'is-bored to accept the shaft 69 and is ofappropriate length to fitbetween the annular support members 64. -As'shownin Fig. 9, the rocker casting 76 is preferably non-rotativelyassociated with the shaft 69, by means such'as keys 78, to insure 4 thatthe relative rotation will occur between the shaft 69 and the surfacesof the bearings 66.

At its lower end, the rocker casting 76 is provided with an enlarged,bored, longitudinally split spindle housing portion 80 (Figs. 1, 3, 8and 10). A spindle assembly 82 (Fig. 8), including a spindle 84 and apulley 86 (Fig. 10), as well as appropriate bearings (not shown) isclamped within the spindle .housing 80 by means such as machine screws88. The spindle 84 supports the grinding wheel 58 (Fig. 8).

To rotatively drive the spindle assembly '32, a motor 92 is mounted uponthe body casting 62 and is provided with a driving pulley 94 coupled tothe-spindlepulley 86 by a belt 96 (Figs. 3 and 10). To maintain theproper tension upon the belt 96 while permitting the use of spindlepulleys S6 of various sizes, and to maintain proper belt tension despiteshifting of the distance between motor pulley 94 and spindle pulley 86during cross-feeding, an idler 100 is rotatively mounted upon a'supportarm 102. Support arm 102 is rotatably' mounted upon a pin 104 affixed'tothe body 62 by means of a bracket 106.

The spindle assembly 82, the spindle housing 80 and the-rocker'76 arerocked on the longitudinal axis of the shaft69 in a controlled,automatic manner to produce automatic cross-feeding. The rocker 76 andspindle housing 8f) are firmly biased in a counterclockwise direction(Fig. 10), i. e., towards the body casting62. A spring is seated withina horizontal socket 112 formed in the-rocker 76. A bolt 114 extendsthrough a bore in the rocker 76 which is coaxial with the socket 112,and through an aligned bore in a web 116 of the body casting 62, and isthere secured by a nut 118. The head of the bolt 114 engages a washer116 which thereby serves to compress'spring'110 to cause a force to beexerted to force the rocker 76 and the spindle housing portion 80 in acounterclockwise direction, towards the body '62. The bolt 114 andspring 110 are preferably centered be tween the support members 64, asis shown in Figs. l and 9 of the drawings.

Rest buttons 120 (Figsp9 and 10) are seated within individual sockets122 near each end of the spindle housing 80, the longitudinal axes ofthe buttons 12% preferably but not necessarily, being coplanar with eachother and with the longitudinal axis of the spindle assembly 82. Thehead of each of the rest buttons 120 engages an individual actuating pin124 slidably mounted in horizontalapertures in the body casting 62. Therear end of each of the actuating pins 124 engages an individualflat 126formed in an otherwise right-circular cylindrical actuating shaft 128.Bearings 132 and 134, seated within aligned apertures in the sidewallsof'thc body'castiug 62,-rotatably support the actuating shaft 128. Theshaft 123 is prevented from moving in translation along its longitudinalaxis in one direction'by a thrust washer 138 (Fig. 9), fastened to theshaft 128 by a set screw 140 or equivalent means, and 'in the otherdirection by engagement of an actuating arm, integral with the shaft,with the side of the body casting, as will be noted As may best beseeninFig. 10 of the drawings, the actuating pins 124 engage the flats 126 ata point or area vertically offset-from the longitudinal axis of theshaft 128. Hence, as the shaft 128 is rotated in aclockwise direction(Fig. 10),forcesareexerted to move the actuating H pins 12410 'IllCleft, :the distance of movement of the actuating pins 124 beingdetermined by the extent of the aforesaid offs'etand by the anglethrough which the shaft 128 is rotated. It isimportauttoprecision-operation that bothactnating pins.124.exertv equalforces to rotate :and hold the spindle housing 80. This is exem plarilyaccomplished by making thetwc flats 126 coplanar. by makingthe.distances between the longitudinal axis of the shaft 128 and thepoints or areas .of contact bctween the actuating pins 124 and the flats126 equalto one another, by making the longitudinal axes of theactuating pins 124 parallel with one another, and by making the shapesof those ends of the two actuating pins 124 which engage the flats 126the same. The ends of the actuating pins 124 engaging the flats 126 maybe spherical or conical to provide point contact, may be cylindrical toprovide line contact, or may be appropriately formed to provide areacontact at a selected position of the shaft 128. The two rest buttons120 and the two actuating pins 124 need not be identical pairs. However,with the longitudinal axes of the shaft 128, the shaft 69, and thespindle assembly 82 all parallel to one another, it is important thatwhen there is solid mechanical contact between the spindle housing 80,one of the rest buttons 120, the associated actuating pin 124 and theassociated flat 126, there should concurrently be equivalent mechanicalcontact between the spindle housing 80, the other rest button 128, theother actuating pin 124 and the other flat 126. This may beaccomplished, for example, by lapping the longer of the notedcombinations until it is exactly the same length as the shorter, or bymanufacturing all parts to close tolerances.

it will therefore be seen that by rotating shaft 128 in a clockwisedirection (Fig. the actuating pins 124 and rest buttons 120 are moved tothe left to exert balanced forces upon the spindle housing 80 to rotatethe rocker assembly 76 about the longitudinal axis of the shaft 69.These balanced forces are opposed by the restoring force of spring 110,which force, as before noted, is applied in a vertical plane centeredbetween the vertical planes which include the longitudinal axes of theactuating pins 124. By virtue of this arrangement, there is no danger ofbinding or of uneven wearing which would tend to cock the spindle axis.

The rotation or oscillation of the shaft 128, and the consequentmovement of the flats 126, is accomplished through an actuating arm 142(Figs. 8 to 10) formed integrally with the shaft 128. In its preferredform, a flat 126 forms the forwardmost face of the arm 142, while therest of the upper portion of the arm 42 is generally circular, buthaving 'a diameter greater than that of the shaft 128 to define a flangeportion 144. This flange portion 144 (Fig. 10) abuts the face of thebody castings 62- or, preferably, the edge of the bearing 134 in orderto prevent translational motion of the shaft 128 in one direction, aspreviously mentioned.

A socket 146 is provided near the lower end of the downwardly dependingportion of the arm 142 to accept a cam follower 148. The end of camfollower 148 is maintained in engagement with a cam 150 by means of aspring 152 (Fig. 10) which engages the forward face of the actuating arm142 and which is mounted upon a spring guide 154 affixed to the bodycasting 62. Cam 158, the configuration of which will be hereinafterdescribed, is mounted upon a cam shaft 158 and is prevented fromrotating with respect thereto by means such as a key 168 (Fig. 9). Camshaft 158 is rotatably supported by bearings 162 and 164, bearing 162being mounted in a bearing sleeve 166 positioned in one wall of the bodycasting 62 and bearing 164 being mounted in a hearing sleeve 168 fixedwithin the aperture in the other wall of the body casting 62 by means ofmachine screws 170 or the like.

At the end of the cam shaft 158 upon which the cam 150 is mounted, theshaft is reduced in diameter and threaded to accept a nut 174. A pair oftiming drums or discs 176 and 178 and a pair of washers 180 and 182 aresandwiched between the nut 174 and the outer face of the side wall ofthe body casting 62. The timing discs 176 and 178 are, in this fashion,secured to the cam shaft 158 and will rotate therewith. As may be seenin Fig. 8 of the drawings, disc 176 is provided, at one point in itsperiphery, with an extending or projecting finger 184 and timing disc178 is provided at one point on its periphery with an extending finger186. A limit switch LS2 (Figs. 8 and 9) is mounted to the body casting62 by means of a mounting bracket 190. The actuating element 192 ofswitch LS2 extends to a point adactuating member 192 thereof is engagedeither by the projecting finger 184 on timing drum 176 or the projectingfinger 186 on the timing drum 178. Switch LS2 serves to terminate therotation of both the workhead motor 18 (Fig. l) and the table drivemotor 32 in a manner and for a purpose hereinafter to be described.

The earn shaft 158 may be automatically rotated under the control of themotion of the table 22 (Fig. 1). Thus, a cam 200 (Figs. 1, 2 and 3) ismounted upon and moves with the table 22. Its position along the tableis preferably adjustable for a purpose hereinafter to be noted. A rockerarm 282 is pivotally mounted relative to the base 28 by a bracket 284.As the table moves from the left to the right (Figs. 1 and 2) duringeach stroke, the cam 280 engages a roller 286 (Figs. 2 and 3) rotatablymounted upon the upper end of the rocker arm 202. As a result, the upperend of the rocker arm 202 is pivoted forwardly (counterclockwise in Fig.3) and the lower end of that rocker arm is caused to move inwardly. Thelower end of rocker arm 202 is bifurcated and apertured to accept a pin28% which also engages an aperture in the end of a generallyhorizontally disposed rocker link 210 (Fig. 3). Rocker link 210 extendsthrough an aperture in the bottom of a socket 212 seated within anaperture 214 in the forward wall of the hollow base portion 28. Acompression spring 216 is trapped between the base of the socket 212 anda washer 218 mounted upon the rocker link 210 and abutting the rear faceof the lower end of the rocker arm 202. As a result, the rocker link 210is biased forwardly so that the roller 206 at the upper end of therocker arm 202 is continuous- 1y forced toward the table 22 in aposition to be engaged by cam 200, the camming action overcoming theforce exerted by spring 216.

Rocker link 210 extends through an aperture 220 formed in a verticalportion of the base 28 and is apertured to accept a pin 222 which alsoengages aligned apertures in the two legs of the bifurcated lower arm ofa feed lever 224 (Figs. 3 and 5). Feed lever 224 operates in the natureof a bellcrank, pivoting about a pin 226 secured to the cross-feed bed29. Pin 226 may conveniently be in the form of a cap screw engaging atapped aperture in the bed 29. The generally horizontally disposed upperarm 228 of the feed lever 224 is longitudinally slotted to accept athreaded link pin 229 which also passes through a bushing 232 (Fig. 5)and is secured by a nut 234. Bushing 232 pivotally supports the lowerend of a ratchet link 23%. At its upper end, ratchet link 238 isrotatably attached, by means of a pin 238, to a feed bracket 248. As maybest be seen in Fig. 7 of the drawings, the feed bracket 248 isrotatably supported upon the cam shaft 158 by means of a bearing 242,hearing 242 being retained upon the cam shaft 158 by means of a screw244 engaging a'tapped aperture in the end of the cam shaft 158 and awasher 246 interposed the head of the screw 244 and the outer faces ofthe cam shaft 158 and the bearing 242.

It will be perceived in Fig. 3 of the drawings that the link pin 238 iseccentrically mounted relative to the axis of rotation of the feedbracket 240. Hence, during each stroke of the table 22, when the cammingsurface strikes the wheel 286, the rocker mm 282 is pivoted to drivetherocker link 2218 a short distance rearwardly of the machine (to theright in Fig. 3), and this motion is communicated through the bellcrankfeed lever 224 and the ratchet link 230 to rotate the feed bracket 248through a small angle in a counterclockwise direction (Fig. 3). As thetable 22 commences its return stroke, the carnming surface 286 is movedaway from the wheel 206 7 and the elements are restored to their normalpositions, as shown, by the spring 216.

This normal position is defined by an adjusting screw 250 (Figs. 3 andthreadedly engaging a bracket 252 aflixed to the cross-feed bed 29, andretained in selected position by a lock nut 254. Screw 250 is adapted toengage the lower surface of the arm 228 of the feed lever 224 thereby toadjustably establish a limit to the clockwise motion of the feed lever224, and hence to establish the length of the stroke of the ratche tint:238 and the angle of rotation of the feed bracket 2%.

A pawl 256 is pivotally mounted upon a pin 25%; (Pig. 7) which extendsthrough an aperture in the feed bracke 240 and is retained on the feedbracket by a washer 260 and nut 262. Pawi 256 is spring biased intoengagement with the teeth on a ratchet 26 which is mounted upon the camshaft Means such as a key 266 is provided to prevent relative rotationbetween the cam shaft 158 and the ratchet 264.

As the feed bracket 240 is rotated through a small angle in acounterclockwise direction (Fig. 3), the engagement between the pawl 256and the ratchet 264 causes the ratchet 26 i, and hence the cam shaft 158(Fig. 7), to be rotated through the same angle. Upon the return stroke,the pawl 256 rides over the teeth of the ratchet 264 to assume itsinitial position, normally in engagement with another tooth, inpreparation for further incremental rotation of the cam shaft 158. Theratchet 264, and hence the cam shaft 158, is prevented from rotating ina clockwise direction (Fig. 3) by means of a ratchet lock 2'79 pivotallymounted upon the body casting .62 and spring biased into engagement withthe teeth of the ratchet 264.

It will now be perceived that the adjusting screw 250 in essencecontrols the size of the angle through which cam shaft 158 is rotatedduring each stroke of the work table 22 by controlling the number ofteeth on the ratchet 264 which are traversed by the pawl 2:36 during itsreturn stroke. In a pragmatic embodiment of the invention, as anexample, the adjusting screw 250 may be positioned to permit variationin the angle of rotation of the cam shaft 153 from a minimum of 1 /2" to12 for each stroke of the table 22.

This incremental rotation of the cam shaft 158 causes the cam 150, keyedthereto, to similarly incrementally rotate, and this incrementalrotation of the cam produces a selected cross-feed of the grinding wheelinto the work, cam rise being translated into spindle movement by thecam follower 1-18. actuating arm 142 and actuating pins 124.

An exemplary configuration of the cam 150 is represented in Fig. 6 ofthe drawings. At the beginning of each cycle of operation, the cam is ina position wherein the cam follower MS is in engagement with thatportion of the cam surface labeled load, i. e., between lines 276 and278. This loading portion of the cam surface is preferably but notnecessarily arcuate and is normally the area of minimum radius from thelongitudinal axis of the cam shaft 158. As a result, the cam follower148 is in its furthest position toward the rear of the machine (towardsthe left in Fig. 8, towards the right in Fig. 9). Hence, the spindlehousing 83 and the grinding wheel 58 (Figs. 1 and 8) are both at theirmost rearward position with any given manual setting of the cross-feedwheel 63 (Fig. l). The cross-feed wheel 63- is preferably initiailyadjusted so that when earn 156 is in this load" position, the grindingwheel 53 is freely insertable within the bore of the workpiece which isto be internally ground.

During the rough grind portion of the earn 156 (Fig. 6), from line 278to line 280 the distance between the longitudinal axis of the cam shaft158 and the cam surface gradually increases. The difference between thedis tance from this center axis to the cam surface at the beginning ofthe rough grind, along lines 278 and the distance at the end of therough grind, along line 280, will be determined by the use to which themachine is being placed, e. g., the amount of material that must beremoved from the inner surface of the workpiece, the expected variationin the rough internal diameters of the workpieces and the rate of rapidin-feed desired. As an example, in practice this may be in the order of10 or 15 thousandths of an inch. The camrning surface must vary by afactor greater than this under the disclosed preferred arrangement inview of the mechanical advantage resulting from the difference in thelever arm between the longitudinal axis of the shaft 128 (Fig. 10) andthe actuating pin 124 and the distance between that longitudinal axisand the axis of the cam follower i4 8. example, this mechanicaladvantage may be in the order of 6 to l, permitting the cam surfaces tobe varied by a factor six times greater than the desired variation atthe work.

Over the first dwell portion of the cam surface (Fig. 6), between lines280 and 282, the surface is arcuate and marks the termination of therapid in-feed. During the dress period, between lines 282 and 284, thecam surface is again preferably arcuate but the radius is less than thatduring the first dwell period so that the grinding wheel is backed offfrom the internal surface of the workpiece by a few thousandths of aninch to insure that there will be no engagement as the grinding wheel iswithdrawn from the workpiece, as will be noted. During the finishperiod, between lines 234 and 286, the cam surface again slowlyincreases in radius so that the grinding wheel is slowly advanced asmall distance to perform a final finish cut. During the final dwellperiod, between lines 286 and 276, the cam surface is preferably againarcuate to perform the finishing off or sparking out" of the workpiece.

The cam 150 may be manually advanced through its cycle, or any portionof a cycle skipped, by rotating an adjusting knob 292. As may best beseen in Fig. 10 of the drawings, the adjusting knob 292 is attached to ashaft 294 by a pin 296, the base of the knob 29 2 resting upon a bushing298 seated upon the upper end of a bored portion 300 of the body casting62.

Shaft 294 is rotatably supported by a bearing 302 seated in a bracket304 rigidly attached to the body casting 62. A miter gear 306 is pinnedor otherwise afiixed to the lower end of the shaft 2% and is engageablewith a mating miter gear 363 (Fig. 9) retained upon the cam shaft 158 bypin 316. Hence, by rotating the knob 292, the gears 396 and 308 arerotated to rotate the cam shaft and cam 150.

In internal grinding, the grinding wheel must be occasionally orregularly dressed in accordance with the degree of precision required.in the disclosed arrangement, a wheel dresser 315 is employed as aprimary element of the automatic control of the grinding to finishedsize. The exemplary wheel dresser, as represented in Fig. 4 of thedrawings, comprises a slotted base 316 provided with means (not shown)for supporting a shaft 318. A longitudinal bore in the dresser body 320engages the shaft 318 and is rotatable thereon between an uprightposition, as shown, and a position displaced from the shown position, inwhich the pedestal portion 322 lies substantially in a horizontal plane.A boss 324 on the body portion 320 is adapted to strike an upstand ingportion 326 on the base 316 accurately to define the upright, workingposition of the wheel dresser 315. A handle 328, aflixed to the pedestalportion 322, facilitates the rotation of the body portion 320 betweenits two positions.

A micrometer barrel 339 is mounted in the upper end of the pedestalportion 322 and is adapted to precisely advance a holder 332, and hencea cutting diamond The selected position of the diamond as established bythe setting of the micrometer 336, is maintained by means of a set screw336.

The wheel dresser 315 is mounted upon the reciprocating table 22 (Figs.1 and 8), the slots in the base 316 thereof (Fig. 4) permitting a roughinitial adjustment in accordance with the size of the grinding wheel 58.The wheel dresser should be in its upright position, as represented inFig. 4, only during the dressing operation and should be lowered so thatit will not strike any portion of the spindle assembly 82 (Fig. 8)during the manual or automatic grinding operation. As insurance that thewheel dresser 315 will not be inadvertently left in its upright positionand damage any portion of the equipment, means such as a stop 34%) (Fig.8) may be mounted upon the body casting 62 in an appropriate position tostrike thev wheel dresser body 320 or pedestal 322 and thereby rotatethe dresser to its horizontal position if the wheel dresser is in itsupright position when the table 22 is moved beyond the point wheredressing could occur. The manner of employing the wheel dresser 315 inconjunction with the previously described automatic crossfeed mechanismto perform repetitive precision grinding operations will best beperceived from a description of the preferred method of employing theequipment to obtain the desired result. Assuming the equipment to be inthe position shown in Fig. 1 of the drawings, the adjusting screw 250(Fig. 3) is adjusted to establish the desired feed rate and then theratchet feed pawl 256 (Fig. 3) is disengaged from the ratchet 264 bydepressing the integral lever 257, thereby disabling the automaticcross-feed. One of the workpieces to be bored is inserted in the chuck14 (Fig. l) and the table feed mechanism is set to the proper position.Assuming that the length of the workpiece to be ground is suflicientlysmall so that the reciprocator may be employed, the stop 44 and the pawl46 are positioned to the requisite position and length of stroke, andthe cam 260 (Fig. 2) is adjusted in position to actuate the rocker arm 2132 at the appropriate time. While this position may be selected so thatthe incremental advance of the cross-feed mechanism will occur at anypoint in the stroke, it has been found preferable to adjust the cam 230so that this incremental advance occurs at the full depth of stroke,i.'e., when the table 22 is at its most rightward position in its cycle.The knob 292 (Fig. 6) is rotated to set the cam 150 in the final dwellposition, i. e., 'so that the cam follower 148 is engaging that portionof the cam surface between lines 286 and 276.

After these preliminary steps, the workpiece is manually ground tofinished size, manually controlling the crossfeed by means of thecross-feed wheel 63. After the workpiece is accurately ground to itsfinished size, the workhead 16 is moved away from the grinding wheel bytraversing the table 22 to the left by means of the hand wheel 30, andthe knob 292 is again rotated to set the cam 150 (Fig. 6) to the dressposition, as shown. The wheel dresser 315 is then rotated to itsoperative position and the micrometer barrel 330 (Fig. 4) thereof isadjusted until the diamond 334 just touches the grinding wheel 58 (Fig.1). It will be perceived that at this instant the point of the diamond334 is precisely positioned in predetermined relationship with theforwardmost portion of the inner surface of the ground workpiece, i. e.,the distance between the longitudinal axis of the chuck 14 and thediamond 334 has been set to a precise relationship with the internalradius of the correctly ground workpiece.

The wheel 58 is preferably dressed at this time by advancing thegrinding wheel 58 into the diamond approximately one thousandth of aninch by turning the crossfeed wheel 63. The second workpiece is theninserted in the chuck 14, the ratchet feed pawl 256 (Fig. 3) isre-engaged, and the adjusting knob 292 (Fig. 6) is rotated to bring theload portion of the surface of the cam 150 into engagement with the camfollower 148. The reciprocator 40 is then engaged by depressing thehandle 50 (Fig. 2) to bring the pawl 46 into operative position,

and the upper end of the bellcrank 40 is trapped between" the stop 44and the pawl 46. The control switches are then set to automaticoperation, after which the machine will automatically grind the secondworkpiece to finished size. It will be observed that if for any reasonsthere has been error in the setting, as determined by measuring theinternal diameter of the second workpiece, compensation may readily bemade by turning the micrometer barrel 330 (Fig. 4) of the wheel dresser315 the appropriate amount in the appropriate direction.

If it is desired to dress the grinding wheel 58 each grinding operationfor precision grinding, or otherwise whenever it is desired to dress thewheel, this operation should be performed whilethe cam follower 148 isengaging the dress portion of the surface of the cam 150 (Fig. 6), asshown.

A control panel 350 may be mounted upon the front of the machine,carrying a plurality of switches SW1 to SW4 by means of which controlmay be exercised over the several motors employed in the apparatus. Forexample, switch SW1 may control the table drive motor 18, switch SW2 maycontrol the workhea-d motor 32, switch SW3 may control the automaticsizing unit spindle motor 92, and switch SW4 may control the coolantpump motor 54.

As is represented in Fig. 11 of the drawings, each of the switches SW1,SW2, and SW4 is adapted to be placed in any one of three positions: anupper position for manual operation of the machine, a lower position forautomatic operation of the machine, and a center, off, position, each ofthose switches being shown in the latter position in Fig. 11 of thedrawings. Switch SW3 has but an upper on and a lower off position.

In the arrangement of Fig. 11 it is assumed that lines L1 to L3 areconnected to a suitable source of threephase power. The voltageappearing between conductors L2 and L3 is applied to the primary windingof a step-down transformer T1, inducing an alternating voltage in thesecondary winding of that transformer, and between conductors L4 and L5,of appropriate magnitude for the control purposes.

If the table-motor controlling switch SW1 is moved upwardly to themanual-control position, the voltage on conductor L4 is applied throughthat switch to the contacts of limit switch LS3. While limit switch LS3is not disclosed in its mechanical details in Figs. 1 to 10 of thedrawings, since those details form no part of this invention, it may benoted that mechanical linkage is or may be provided which is adjustableto define two limit positions of motion of the table 22 for powerreciprocation of that table. When the table is at its selected leftmostposition, limit switch LS3 is moved upwardly (Fig. 11) to complete anenergizing circuit for relay TF which closes its contacts TFa to TFc tocause the table motor 32 to rotate in an appropriate direction to movetable 22 to the right (Fig. 1). When the table 22 reaches its selectedright-hand limit position, the mechanical linkage moves limit switch LS3to its lower position (Fig. 11) to release relay TF and to operate relayTR, whereupon relay TR closes its contacts TRa to TRc to cause tablemotor 32 to be rotated in the opposite direction to move table 22 backto the left (Fig. 1). When this power feed mechanism is not beingemployed, i. e., whenever the table 22 is being reciprocated either byhand or by the reciprocator mechanism 40, the limit switch LS3 is movedto its upper position (Fig. 11) so as continuously partially to completean energizing circuit for relay TF. However, when the table is beingmanually reciprocated by hand wheel 30 (Fig. 1) switch SW1 is placed inits ofl? position, as shown, so that relay TF cannot operate.

When the head-motor controlling switch SW2 is moved to its upper,manual-control position, control of the head relay H is bestowed uponon-ofi switch SW5 which may be conveniently located upon the machine.When relay H is operated, its contacts I-la to He are closed to apply 11the three-phase alternating voltage between conductors L1 to L3 to thehead motor 18.

The spindle motor 92 is controlled by on-off switch SW3 and relay S.During either manual or semiautomatic operation of the mechanism, motor92 runs continuously.

When the pump-motor controlling switch SW4 is moved upwardly to itsmanual-control position, relay P is operated to cause pump motor 54continuously to rotate.

To prepare for semiautomatic operationof the machine, switch SW3 ismoved to its closed position, and switches SW1, SW2, and SW4, are moveddownwardly to their automatic-control positions.

As previously described, limit switchLSl (Fig. l) is momentarily trippedwhenever table 22 is moved back to the right from its leftmost limitposition. It is assumed that limit switch LS1 contains a Single normallyopen contact (Fig. 11).

The other controlling limit switch LS2 (Fig, 8) is assumed to beprovided with a single normally closed contact which is opened wheneveractuator 192 is forced inwardly by either projecting finger 184 orprojecting finger 186. The timing discs 176 and 178 are, in thepreferred arrangement, so oriented that the projecting finger 184strikes the actuator 192 at the commencement of the dress interval (Fig.6), and that the projecting finger 186 strikes the actuator 192 ofswitch LS2 at the beginning of the load position.

in the circuits of Fig. 11, limit switches LS1 and LS2 are shown in aposition corresponding to the position of the machine as represented inFigs. 1 to of the drawings, that is, the table 22 (Fig. 1 is not at itsleftwardmost position, so that limit switch LS1 is in its normally openposition, and neither projecting finger 184 nor 186 (Fig. 8) is inengagement with actuator 192 of limit switch LS2 so that limit switchLS2 is in its normally closed position (Fig. ll).

To institute semiautomatic operation of the machine, table 22 istraversed to its leftmost position to facilitate loading of theworkpiece, and is then traversed to the right by the handwheel 30.During the course of this travel, limit switch LS1 (Fig. 11) ismomentarily closed. Upon its closure, a circuit is completed fromconductor L4, the lower pair of contacts of switch SW2, limit switch LS2(No. 1 contacts), conductor L6, limit switch LS1, winding of relay TD2,to conductor L5. Relay TD2 is a time delay relay having one normallyopen instantaneously closing contact TD2i and one normally opentime-delay contact TD2d. Immediately upon the operation of relay TD2,its contacts TD21' are closed to complete a holding or sealing circuitfor unit TD2 through that instantaneous contact TDZI', and throughnormally and now closed contacts He to conductor L6. Consequently, timedelay unit TD2 remains operated when limit switch LS1 again opens afterits momentary closure.

After the preselected time interval, contacts TD2d are closed tocomplete a circuit from conductor L6, contacts TD2d, conductor L7, lowercontact of switch SW1, upper contact of limit switch LS3 and through thewinding of relay TF to conductor L5 whereupon relay TF is operated toinitiate the rotation of table motor 32. Additionally, the voltage onconductor L7 is applied through the middle contact of switch SW2 toenergize relay H and hence to institute rotation of the head motor 18,and through the lower contact of switch SW4 to start pump motor 54.

Relay H, in operating, closes its normally open contacts Hd whichcompletes a holding or sealing circuit for relay H to conductor L6 andwhich completes holding or sealing circuits for relays TF and P byinterconnecting conductors L6 and L7 through the middle contact ofswitch SW2. Hence, the head motor 18, the table motor 32 and the pumpmotor 54 continue to rotate even though contact TDZd is opened.

Means are provided to open contact TDZd by releasing time delay unit TD2 in order to restore that relay to normal in preparation for itsrepeated function in the next cycle. This means comprises the normallyclosed contact He of relay H which opens when relay H operates tointerrupt the looking or sealing circuit for relay TD2, whereupon timedelay relay TD2 releases and contacts TD2d are opened.

it will be appreciated that the function of unit TD2 is to interpose adelay after limit switch LS1 (Fig. 1) is tripped to allow the operatortime to easily re-engage the reciprocator 40 between the stop 44 and thelatch 46.

The cycle of operation continues until the cam (Fig. 6} reaches itsdress position, as shown. At the beginning of this period, theprojecting finger 184 (Fig. 8) on timing disc 176 will strike and movethe actuating member 192 of limit switch LS2, opening that limit switch.

When the No. 1 contacts of limit switch LS2 are opened (Fig. l l), thescaling or holding circuits for relays H, TF and P are interrupted,those relays release, and the head motor 18, the table motor 32 and thepump motor 54 stop.

Upon this indication, the operator releases the latch 46 (Fig. l),traverses the table to the left, and proceeds to press the wheel, ifdressing each cycle is performed. The operation of the Workhead motor18, of the table drive motor 32 and of the pump motor 54 is reinstitutedby limit switch LS1. However, it is possible that the termination of theoperation of the table reciprocator will occur while finger 184 (Fig. 8)is engaging actuator 192 of limit switch LS2 in which case limit switchLS2 (Fig. 1) will remain separated from its No. 1 contact and the motorscannot be re-energized. To avoid this possibility, limit switch LS2 isprovided with a No. 2 normally open contact which is closed when eitherfinger 184 or 186 (Fig. 8) strikes the actuating arm 192. Upon theclosure of limit switch LS2 to its No. 2 contact, a circuit is completedto energize time delay unit TD1. Time delay unit TDl is a time delayrelay which functions to so modify the circuit conditions that after itsdelay period it is as if limit switch LS2 were again closed to its No. 1contact even though limit switch LS2 has not been released by finger 184or 186. Thus, a preselected delay interval after the energization ofrelay TDl, contacts TDla, connected in shunt of the No. 1 contacts oflimit switch LS2, are closed. Hence, the subsequent closure of limitswitch LS1 will re-energize motors 32, 18 and 54. The resultantreciprocation of the table will step the timing drums 176 and 178 (Fig.8), limit switch LS2 will reclose to its No. 1 contact and time delayunit TDI will become de-energized.

The cycle then proceeds to completion, its termination being denoted bythe engagement of the cam follower 148 (Fig. 6) with the load portion ofthe surface of the cam 150. At this point, projecting finger 186 ontiming disc 178 will open limit switch LS2 and the rotation of the chuck14 (Fig. 1) and the reciprocation of the table 22 will be terminated asbefore. This will signal the operator to release latch 46 and traversethe table 22 to the left by handwheel 30 preparatory to removing theworkpiece and reloading the chuck.

While it will be apparent that the embodiment of the invention hereindisclosed is well calculated to fulfill the object above stated, it willbe appreciated that the invention is susceptible to modification,variation and change without departing from the proper scope or fairmeaning of the subjoined claims.

What is claimed is:

1. In a grinding machine or the like, a body member, a spindle assembly,pivot means for pivotally supporting said spindle assembly upon saidbody member, spring means tending to pivot said spindle assembly in onedirecengageable with both of said pins for concurrently shifting theposition of both of said pins relative to said body member for pivotingsaid spindle assembly relative to said body member.

2. In a grinding machine or the like, a body member, a spindle assembly,pivot means for pivotally supporting said spindle assembly upon saidbody member, spring means tending to pivot said spindle assembly in onedirection upon and relative to said body member, means including a pairof spaced-apart pins both at one side of said spindle assembly forestablishing an adjustable limit position to movement of said spindleassembly in said one direction, and power driven means for concurrentlyand identically shifting the positions of both of said pins relative tosaid body member for pivoting said spindle assembly relative to saidbody member.

3. In a grinding machine or the like, a body member, a spindle assembly,means including a spindle-assembly housing movably supporting saidspindle assembly relative to said body member, spring means tending tomove said spindle assembly in one direction relative to said bodymember, a shaft rotatably supported in said body member, means forrotating said shaft, a pair of spaced-apart actuating surfaces integralwith said shaft, and a pair of parallel actuating pins engaging saidsurfaces and said housing.

4. In a grinding machine or the like, a housing, a spindle assemblymounted in said housing, a body member, a shaft supported in said bodymember, means for rotatively supporting said housing upon said shaft,the longitudinal axes of said shaft and said spindle assembly lying inspaced parallelism with one another, a pair of spaced-apart, parallelactuating pins engageable with said housing, means for moving said pins,and spring means acting along a line parallel with and intermediate saidpins for maintaining said housing in engagement with said pins.

5. In a grinding machine or the like, a body member, a spindle assemblymovably supported by said body memher, a cam shaft rotatably supportedby said body member, means including said cam shaft for moving saidspindle assembly relative to said body member, a table, means forreciprocating said table, and means actuated by said table for rotatingsaid cam shaft.

6. In a grinding machine or the like, a base, a table, means forreciprocating said table, a rocker arm mounted on said base, a cam onsaid table engageable with said rocker arm, a spindle assembly, a shaft,means including said shaft for moving said spindle assembly transverselyof said table, and means actuated by said rocker arm for rotating saidshaft.

7. In a grinding machine or the like, a base, a table, means forreciprocating said table, a rocker arm mounted on said base, a cam onsaid table engageable with said rocker arm, a spindle assembly, a shaft,means including said shaft for moving said spindle transversely of saidtable, and means actuated by said rocker arm for rotating said shaftcomprising a ratchet mounted on said shaft, a pawl engageable with saidratchet, and linkage means actuated by said rocker arm for reciprocatingsaid pawl.

8. In a grinding machine or the like, a body member, a spindle assemblymovably supported by said body member, a cam shaft rotatably supportedby said body member, means including said cam shaft for moving saidspindle assembly relative to said body member, a table, means includinga motor for reciprocating said table, means actuated by said table forrotating said cam shaft, a timing drum mounted on said cam shaft, aswitch actuated by said timing drum, and means controlled by said switchfor deenergizing said motor.

9. In a grinding machine or the like, a body member, a spindle assemblymovably supported by said body member, a cam shaft rotatably supportedby said body member, means including said cam shaft for moving saidspindle assembly relative to said body member, a table, means includinga motor for reciprocating said table, means actuated by said table forrotating said cam shaft, a timing drum mounted on said cam shaft, 8.switch actuated by said timing drum, means controlled by said switch fordeenergizing said motor, and means effective a selected interval afterthe actuation of said switch for disabling said switch to control saidmotor.

19. In a grinding machine or the like, a base, a table movably supportedon said base, latch means on said table, a motor, table reciprocatormeans driven by said motor and selectively engageable with said latchmeans, manua'lly controlled means for traversing said table between aposition at which said reciprocator means is engaged with said latchmeans and a limit position at which said reciprocator means isdisengaged from said latch means, and switch means actuated when saidtable is traversed from said limit position for energizing said motor.

11. In a grinding machine or the like, a base, a table movably supportedon said base, latch means on said table, a motor, table reciprocatormeans driven by said motor and selectively engageable with said latchmeans, manually controlled means for traversing said table between aposition at which said reciprocator means is engaged with said latchmeans and a limit position at which said reciprocator means isdisengaged from said latch means, switch means actuated when said tableis traversed from said limit position, and means eifective a timedinterval after said switch means is actuated for energizing said motor.

12. In a grinding machine or the like, a base, a table movably supportedon said base, latch means on said table, a motor, table reciprocatormeans driven by said motor and selectively engageable with said latchmeans, manually controlled means for traversing said table between aposition at which said reciprocator means is engaged with said latchmeans and a limit position at which said reciprocator means isdisengaged from said latch means, a workhead including a motor mountedon said table, and switch means actuated when said table is traversedfrom said limit position for energizing both of said motors.

13. In a grinding machine or the like, a base, a table movably supportedon said base, latch means on said table, a motor, table reciprocatormeans driven by said motor and selectively engageable with said latchmeans, manually controlled means for traversing said table between aposition at which said reciprocator means is engaged with said latchmeans and a limit position at which said reciprocator means isdisengaged from said latch means, a body member supported on said base,a cam shaft rotatably supported by said body member, means actuated bysaid table for rotating said cam shaft, a timing drum mounted on saidcam shaft, a first switch actuated by said timing drum, a second switchactuated when said table is traversed from said limit position, andcircuit means including said switches for controlling said motor.

14. In a grinding machine or the like, a base, a table, means forreciprocating said table, a rocker arm mounted on said base, a cam onsaid table engageable with said rocker arm, a spindle assembly, a shaft,means including said shaft for moving said spindle transversely of saidtable, a ratchet mounted on said shaft, a pawl engageable with saidratchet, linkage actuated by said rocker arm for reciprocating saidpawl, and means for adjusting the length of stroke of said pawl.

References Cited in the file of this patent UNITED STATES PATENTS595,065 Jones Dec. 7, 1897 623,742 Rivett Apr. 25, 1899 1,294,541Rundquist Feb. 18, 1919 1,662,241 Drake Mar. 13, 1928 1,756,646 Judge etal Apr. 29, 1930 2,334,938 Lang Nov. 23, 1943 2,647,348 Hahn Aug. 4,1953

